1. Field of the Invention
A simple alternative to known filters having full flow and bypass filters located in common housings is described and claimed.
2. Description of Related Art
Known filter systems for automotive or other applications commonly utilize one of two full flow filter and bypass filter configurations. One such configuration is an arrangement having two separate filtering systems, with a full flow system, which may include more than one filter, depending on flow requirements, and a bypass filter system, which processes only a small percentage of the full fluid volume. In such a configuration, an in-line, series approach is often utilized, with a full flow filter provided downstream of a bypass filter. These systems typically introduce additional costs and components for the automotive assembler and service industry to handle and manage. Vehicle weight is increased as well. U.S. Patent application publication 2008/0078716 to Farmer discloses one such in-line, series approach to filtering.
Evolutions of this configuration include systems having filters with full flow and bypass media stacked upon each other in the same filter housing. Examples of filters having stacked media include apparatuses disclosed by U.S. Patent application publication 2005/0252838 to Fisher and U.S. Pat. No. 5,447,627 to Loafman et al., U.S. Pat. No. 6,319,402 to Schwandt et al., and U.S. Pat. No. 6,350,379 to Roll et al. These sorts of arrangements, however, can reduce the overall capacity for the full flow and bypass filter media.
Further developments have provided increased filtering capacity in the same or smaller footprint, while also offering high efficiency bypass filtration to “polish” the fluid system and provide integral soot filtration, by fitting bypass filters concentrically within full flow filters. U.S. Pat. No. 6,666,968 to Smith et al., U.S. Pat. No. 6,787,033 to Beard et al., U.S. Pat. No. 7,014,761 to Merritt et al., and U.S. Pat. No. 7,090,773 to Meddock et al. provide examples of such developments. The disclosure of each of these U.S. patents is incorporated herein by reference in its entirety as non-essential subject matter.